Sequential estimation of a location parameter and powers of a scale parameter from delayed observations

The problem of sequentially estimating a location parameter and powers of a scale parameter is considered in the case when the observations become available at random times. Certain classes of sequential estimation procedures are derived under an invariant balanced loss function and with the observation cost determined by a convex function of the stopping time and the number of observations up to that time.     

基于背包问题的散货航次方案优选方法研究

针对散货航运市场的航次方案优选问题,使得公司能够在自身的能力约束下获得最大收益,最终目标是快速地在潜在的商业机会中找出最优的航次方案组合。通过调研定义了合理的航次收益、成本定量预估方法,在此基础上结合背包问题构建了航次方案优选模型,并进行改进,从而快速地求解航次方案优选问题,提高企业的核心竞争力。     

Why the Generalized Bass Model leads to odd optimal advertising policies

We show that the optimal advertising strategy under the Generalized Bass Model (GBM) involves beginning at an extremely low level (the lower the better) and then increasing spending throughout the planning period. This strategy remains optimal in the presence of decreasing prices that affect both margins and diffusion speed. We provide a simple explanation for why this happens. We further show that the intuitively appealing patterns of continuous decrease or increase-then-decrease (both with an uptick towards the end) identified in earlier research are also possible as optimal dynamic advertising paths under the GBM structure, but only if the advertising at launch is constrained to be higher than a particular threshold, which we identify. The constraint necessary to generate intuitively appealing strategies lowers overall profits. Therefore, the GBM generates advertising policy recommendations that most marketers would deem odd. This casts doubt on the value of the GBM for normative purposes. Other existing diffusion models are preferred when seeking normative guidance on optimal dynamic advertising policies for new products subject to word of mouth.     

几何布朗运动市场中的最优变现策略研究

利用相对价格冲击函数的Box-Cox变换和存在比例交易费用的线性函数,研究了非瓦尔拉斯均衡金融市场上风险资产的价格变现策略,当资产价格变化服从几何布朗运动时,资产变现时间内生情形下投资者最优变现策略问题可以转化为具有随机跳出时间的随机最优控制,通过对带有广义狄利克雷边界条件的贝尔曼方程的粘性求解,可以实现最优变现策略。     

国际碳排放权交易价格决定与最优出口规模研究

本文分析了总量控制和交易、基准排放和信用两种碳排放权交易体系中的价格决定原理,并以边际减排成本等于市场均衡价格为基础,分析《京都议定书》框架下国际碳排放权交易规模和利益分配不公等情况;然后构建两阶段模型,讨论“非附件B国家”碳排放权出口规模的决定因素及其影响效应,并通过估测中国碳排放权出口规模决定因素的函数值或参数值,计算中国第1承诺期的最优出口量;最后提出中国参与国际碳排放权交易的政策建议。     

中国最优居民消费率的估算及变动机制分析

1978年以来,我国居民消费率的变动特征表现为长期波动下降。为判断居民消费率的运行情况,根据代表性家庭效用最大化估算出最优居民消费率。研究表明,1978-1990年,实际居民消费率与最优居民消费率基本吻合; 1991- 2000年,实际居民消费率平均低于最优居民消费率7.8个百分点;2001-2010年,实际居民消费率平均低于最优居民消费率18.3个百分点。对居民消费率偏低贡献率的分析表明,城镇居民消费率偏低是导致整体居民消费率偏低的主要原因。通过考察预期收入、利率和效用函数改变对最优居民消费率的影响,分析了居民消费率的变动机制。     

Interest rate rules, inflation and the Taylor principle: an analytical exploration

Summary. The purpose of this article is to characterize optimal interest rate rules in the framework of a dynamic stochastic general equilibrium model, and notably to scrutinize the “Taylor principle”, according to which the nominal interest rate should respond more than one for one to inflation. This model yields explicit solutions for the optimal rule. We find that the elasticity of response depends on numerous factors, such as the degree of price rigidity, the autocorrelation of the underlying shocks, or which measure of inflation is used. In general the optimal elasticity of the interest rate with respect to inflation needs not be greater than one.Received: 6 November 2003, Revised: 17 August 2004 JEL Classification Numbers: E5, E52, E58.J.-P. Bénassy: I wish to thank Daniel Laskar and an anonymous referee for their perceptive comments on earlier drafts of this paper. Of course all remaining deficiencies are mine.     

Optimal interest-rate rules and inflation stabilization versus price-level stabilization

This paper compares the properties of interest-rate rules such as simple Taylor rules and rules that respond to price-level fluctuations (called Wicksellian rules) in a basic forward-looking model. By introducing appropriate history dependence in policy, Wicksellian rules perform better than optimal Taylor rules in terms of welfare, robustness to alternative shock processes, and are less prone to equilibrium indeterminacy. A simple Wicksellian rule augmented with a high degree of interest rate inertia resembles a robustly optimal rule, i.e., a monetary policy rule that implements the optimal plan and that is also completely robust to the specification of exogenous shock processes.     

Optimal adaptation strategies to face shocks on groundwater resources

We consider an exogenous and reversible shock to a groundwater resource, namely a decrease in the recharge rate of the aquifer. We compare optimal extraction paths and the social costs of optimal adaptation in two cases: under certainty, i.e. when the date of occurrence of the shock is known, and under uncertainty, when the date of occurrence of the shock is a random variable. We show that an increase in uncertainty leads to a decrease in precautionary behavior in the short run and to an increase in precautionary behavior in the long run. We apply our model to the particular case of the Western la Mancha aquifer in Spain. We show that, in this context, it is advantageous for the water agency to acquire information on the date of the shock, especially for high-intensity and intermediate-risk events.     

Optimal portfolios with a positive lower bound on final wealth

We consider the determination of optimal portfolios under a lower bound on the final wealth. Possible applications range from capital guarantee strategies over life insurance investment where part of the benefit is a guaranteed return on capital to continuous-time mean-variance problems with a strictly positive lower bound. Our solution method consists of transforming the original problem into a portfolio problem without a positive lower bound but a transformed utility function and a modified initial wealth.